Fruits are not the only vitamin C containing plant foods. In fact, red bell pepper beats out most fruits in the vitamin C department at 95mg per 1/2 cup and 3.5 ounces of parsley packs a vitamin C wallop of 125 to 300mg. Brocolli and Brussels sprouts are no slouches either. But most people don't want to snack on these foods and often wonder which fruits have the most vitamin C, besides oranges, which really are a great source but not the true champions. There is a lot more to good nutrition than individual vitamins and all these fruits have an abundance of other vitamins, minerals, and phytonutrients, not to mention fiber.

A coenzyme is a small organic molecule that combines with an enzyme and causes that enzyme to become active or which facilitate its activity. In general, molecules that combine with enzymes in this way are called cofactors, but when the molecules are organic, rather than simple ions of elements, they are called coenzymes. Even though they are organic molecules, coenzymes are not proteins, as enzymes are, and they are not catalytically active themselves, which perhaps makes cosubstrate or cofactor a less confusing name for them. In many reactions catalyzed by enzymes, electrons or groups of atoms are transferred from one compound to another, and this usually involves a coenzyme, which temporarily accepts the group being transferred.

Sources and Physiologic Functions

Sources

Liver, kidney, muscle meats, eggs, cheese, milk, and fish are excellent sources of vitamin B12. It is not found in plant foods or in yeast. Fermented foods such as soy sauce, tempeh, and miso, and fortified foods such as soymilk are also good sources of this vitamin.

Vitamin B12 is essential for DNA synthesis and for cellular energy production. This review aims to outline the metabolism of vitamin B12, and to evaluate the causes and consequences of sub-clinical vitamin B12 deficiency. Vitamin B12 deficiency is common, mainly due to limited dietary intake of animal foods or malabsorption of the vitamin. Vegetarians are at risk of vitamin B12 deficiency as are other groups with low intakes of animal foods or those with restrictive dietary patterns. Malabsorption of vitamin B12 is most commonly seen in the elderly, secondary to gastric achlorhydria. The symptoms of sub-clinical deficiency are subtle and often not recognized. The long-term consequences of sub-clinical deficiency are not fully known but may include adverse effects on pregnancy outcomes, vascular, cognitive, bone and eye health.